With a continually expanding footprint that now exceeds two billion users, the Internet has become an increasingly important medium for information exchange. Businesses, governments, nonprofit organizations, informal social groups, and individuals routinely use the Internet to disseminate information, conduct advertising and public relations campaigns, engage in transactions, and communicate with each other. Given the wide range of content that is available online, as well as the vast quantity of users trying to locate specific content items, the viability of any online resource depends largely on its ability to deliver content that closely corresponds to consumer interest. As a result, website owners, marketers, and other content providers devote substantial resources to identifying specific consumer segments and generating content that is targeted to such segments. In general, understanding how users of an online resource, such as website visitors, can be segmented enables content providers to more effectively deliver targeted content and, ultimately, improve user experience.